Science (English Medium) Class 11 - CBSE Question Bank Solutions

There are four men and six women on the city council. If one council member is selected for a committee at random, how likely is it that it is a woman?

A fair coin is tossed four times, and a person win Re 1 for each head and lose Rs 1.50 for each tail that turns up.

From the sample space calculate how many different amounts of money you can have after four tosses and the probability of having each of these amounts.

Three coins are tossed once. Find the probability of getting

1. 3 heads
2. 2 heads
3. at least 2 heads
4. at most 2 heads
5. no head
6. 3 tails
7. exactly two tails
8. no tail
9. atmost two tails.

In a lottery, person chooses six different natural numbers at random from 1 to 20, and if these six numbers match with the six numbers already fixed by the lottery committee, he wins the prize. What is the probability of winning the prize in the game? [Hint: order of the numbers is not important.]

Check whether the following probabilities P(A) and P(B) are consistently defined

P(A) = 0.5, P(B) = 0.7, P(A ∩ B) = 0.6

Check whether the following probabilities P(A) and P(B) are consistently defined

P(A) = 0.5, P(B) = 0.4, P(A ∪ B) = 0.8

Fill in the blank in following table:

Fill in the blank in following table:

Fill in the blank in following table:

A box contains 10 red marbles, 20 blue marbles and 30 green marbles. 5 marbles are drawn from the box, what is the probability that all will be blue?

4 cards are drawn from a well-shuffled deck of 52 cards. What is the probability of obtaining 3 diamonds and one spade?

From the employees of a company, 5 persons are selected to represent them in the managing committee of the company. Particulars of five persons are as follows:

A person is selected at random from this group to act as a spokesperson. What is the probability that the spokesperson will be either male or over 35 years?

If 4-digit numbers greater than 5,000 are randomly formed from the digits 0, 1, 3, 5, and 7, what is the probability of forming a number divisible by 5 when, the digits are repeated?

The number lock of a suitcase has 4 wheels, each labelled with ten digits i.e., from 0 to 9. The lock opens with a sequence of four digits with no repeats. What is the probability of a person getting the right sequence to open the suitcase?

Find the mean and standard deviation using short-cut method.

Find the mean, variance and standard deviation using short-cut method.

From the prices of shares X and Y below, find out which is more stable in value:

An analysis of monthly wages paid to workers in two firms A and B, belonging to the same industry, gives the following results::

(i) Which firm A or B pays larger amount as monthly wages?

(ii) Which firm, A or B, shows greater variability in individual wages?

If A and B are two set such that \[A \subset B\]then find: 

\[A \cap B\]

If A and B are two sets such that \[A \subset B\] then find: 

\[A \cup B\]